Clinicopathological and Dermoscopic Baselines in Patients with Lynch Syndrome

Simple Summary Lynch syndrome (LS) is an inherited condition that increases the probability of developing colorectal cancer, endometrial cancer and other malignancies. To date, there are no studies about the dermatological baselines in LS patients; herein, we carried out an observational and monocentric study on the main dermatological features in a population of patients with an established LS, to identify the main clinical and dermoscopic features. This work highlights that the phototype of LS patients reflects the main phototype of the geographic area where the survey was conducted (Italy, with phototype II and III). No specific associations with certain skin manifestations emerged, and the clinical and dermoscopic appearance of the pigmented lesions reflected the features present in the general population and in a control group. There are currently no guidelines for skin screening in LS patients and there is insufficient evidence to ensure increased surveillance in patients with LS. Despite the fact that Lynch Syndrome (LS) patients may also develop extra-colonic malignancies, research evaluating the association between LS and skin cancers is currently very limited. We performed a monocentric clinical and dermoscopic study involving 42 LS patients which referred to the Dermatology Unit for cutaneous screenings. In total, 22 patients showed a mutation in MLH1 and 17 patients a MSH2 mutation. Out of the entire cohort, 83% of LS patients showed brown hairs and 78% brown eyes, and the most frequent phototypes were III and II (respectively, 71.5% and 21%). A positive medical history for an internal malignancy was present in 36% of patients, with colon cancer as the most frequent malignancy in 60% of cases. A total of 853 cutaneous lesions have been analyzed: 47% of patients showed a total number of nevi > 10. The main observed dermoscopic features were a uniform reticular pattern (77% of patients), a mixed pattern (9% of patients) and a uniform dermal pattern (14% of patients). Eruptive cherry angiomas were present in 24% of cases, eruptive seborrheic keratosis in 26% and viral warts in 7% of cases; basal cell carcinoma was detected in 7% of cases. We have not found specific associations with specific skin manifestations, and the clinical and dermoscopic appearance of the pigmented lesions reflected the features present in the general population. To date, there are currently no guidelines for skin screening in LS patients. According to our study, there is insufficient evidence to ensure increased surveillance in LS patients; further studies with larger samples of patients are needed to better investigate dermatological and dermoscopic features in LS carriers.